IMMERSIVETOUCH(R) VIRTUAL REALITY-HAPTIC NEUROSURGERY SIMULATOR: CRANIOTOMY AND ANEURYSM CLIPPING Founded by principal investigator Dr. Pat Banerjee, ImmersiveTouch,(R) Inc. (Westmont, Illinois) is a small business that develops fully immersive, visio-haptic virtual reality software engineered into a hardware workstation for the training of surgical residents. The Company's simulator provides residents with repeated, collocated virtual reality-haptic practice needed to accelerate learning and impart skills for the operating room without risk to patients. Brain (intracranial) aneurysm rupture is common and is associated with high mortality and morbidity. The surgical treatment of aneurysms is challenging, requiring a long training period. Such training is mandated. The ACGME Residency Review Committee for Neurological Surgery stipulates that resident case load should include craniotomies for trauma, neoplasms, aneurysms, and vascular malformations. Since the ImmersiveTouch simulator has already been educationally validated for ventriculostomy, we propose here to validate it for aneurysm clipping at the MCA (middle cerebral artery) bifurcation. There is increasing pressure on resident training in classic microneurosurgery by open craniotomy and aneurysm clipping. This is due to a reduction in resident work hours and a decreasing case load in aneurysm clipping, with more than half of simpler aneurysms treated with endovascular means. Additional means of training neurosurgeons to become competent at aneurysm clipping is now necessary. At University of Illinois at Chicago, which is a project partner along with University of Chicago, more than 90 percent of aneurysms requiring clipping form on arteries that arise from the internal carotid artery, including the MCA at the M1-M2 branch? This surgery is performed through a pterional craniotomy followed by dissection along the Sylvian fissure (where the MCA, its branches, and the aneurysm are located). The simulation will teach a pterional craniotomy, dural opening, navigation along a pre-dissected Sylvian fissure, clipping of the aneurysm and blood flow testing to ensure adequate clipping and patency of the adjacent vessels. Phase I converted patient CT voxel data into a 3D virtual reality-haptic model of an MCA bifurcation aneurysm and the Sylvian fissure, etc. We also modeled aneurysm clips in 3D. Phase II focuses on programming the simulator for craniotomy, dural opening, and aneurysm clipping, and on validation.